Ejector nozzle for jet engines



United States Patent EJECTOR NOZZLE FOR JET ENGINES 5 Claims, 6 DrawingFigs.

US. Cl. ..239/265.35,

60/232; 244/56: I8l/33.22l Int. Cl B646 15/04 Field ofSearch..239/265.19,

265.31, 265.33, 265.35; 60/232; 181/33.22l; 244/l2A,53,54,56

References Cited UNITED STATES PATENTS 3/1967 Greulich 3,416,754 12/1968Pinaireetal Primary Examiner-M. Henson Wood, Jr. AssistantExaminer-Michael Y. Mar Attorney-William K. Serp ABSTRACT: The exhaustjet of the illustrated aircraft propulsion means may be selectivelydirected in a downward direction to provide the vertical thrustnecessary for takeoff and landing of the aircraft. Positioned about theprimary exhaust nozzle of the engine is a secondary nozzle whichcomprises a pair of nested cylindrical segments. A first cylindricalsegment is secured to the airframe of the aircraft and defines alongitudinally oriented elongated opening which is downwardly directedto permit passage of the primary nozzle therethrough during verticalflight. A second cylindrical segment similarly defines an elongatedopening and is rotatable about its axis with respect to the firstcylindrical segment. During vertical flight, the openings are placed inregistration, and the primary nozzle is positioned therethrough. Duringcruise flight, the second cylindrical segment is rotated with respect tothe first segment to provide a continuous shield about the primarynozzle.

Patented Nov. 24, 1970 I of2 Sheet II I ..l .i k v .I w

Patented Nov. 24, 1970 Sheet This inventiongenerally relates to anejector nozzle and more particularly relates to an ejector nozzleparticularly adapted for thrust vectoring the exhaust jet of the enginesof vertical takeoff and landing (VTOL) and short takeoff and landing(STOL) aircraft.

Nozzle arrangements adapted to facilitate the fresh air intake of jetengines are relatively well-known. With such conventional constructions,flap segments are opened downwardly so as to allow unobstructed verticalthrust vectoring of the engine. Such a configuration, however, adverselyinfluences the aerodynamic performance of the aircraft. In addition, aconsiderable number of complex subassemblies are required for obtainingthe synchronized control of the tilting movement and for mounting theindividual flaps to the airframe structure.

Alternate arrangements for jet engine ejector nozzles for fresh airintake are known wherein the ejector nozzle is axially shifted alongthe'jet exhaust pipe. Such configurations have relatively low dragduringcruise flight, however, and increase the complexity of theactuating, guiding, and retaining apparatus.

A main feature of the illustrated embodiment is the avoidance of thetilting nozzle segments of known constructions. this feature is obtainedby rotating a portion of the secondary nozzle so as to align anelongated opening defined thereby with the lower end of the fuselage toallow the primary nozzle to extend downwardly for vertical thrustvectoring.

Briefly, with reference to the illustrated embodiment, a secondarynozzle consisting of two nested cylindrical sections is positioned aboutthe jet engine primary nozzle which tilts downward during verticaltakeoff and landing. The upwardly disposed cylindrical segment isrigidly fixed to the airframe. The lower section, however, is rotatableabout the longitudinal axis of the engine. It should be noted that thisarrangement eliminates the need for doors, as well as actuating andsynchronizing mechanisms for their operation.

The illustrated embodiment provides for the lower cylindrical section tobe rotated through 180 with respect to the upper tube section. Further,each of the tubular sections is in a common symmetry plane, and theirparallel horizontal axes are vertically offset. The illustratedembodiment includes locking facilities located at the longitudinal edgesof each of the sections. The sections are provided with fresh air intakeports located in the exhaust regions of the primary nozzle.

A main object of thisinvention is to provide an improved ejector nozzlefor a jet engine. Other objects and advantages of the invention willbecome apparent with reference to the following description andaccompanying drawings which show an illustrative embodiment of thisinvention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a longitudinalcross-sectional view of the propulsion means of an aircraft includingcertain-features of this invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

FIG. 3 is a cross-sectional view taken along the line Ill-III of FIG. 1.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 2. vFIG. 5 is a cross-sectional view taken along the line V-V of FIG. 1.

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, a jetengine 10 is illustrated which is installed in the airframe of a VTOLaircraft. A secondary nozzle is positioned about a tiltable primaryexhaust nozzle 11 of the engine 10. The secondary exhaust nozzlecomprises an outer segment 22 and nested segment 21. The inner segment21 is an extension of the nozzle body 50, the latter of which is securedto the airframe at a point in front of the segment 21, a space existsbetween the segment 21 and the airframe which space receives the innersegment 22 which is rotatable through l about its longitudinal axis. Forillustration purposes the segment 21 will be shown and described asbeing fixed to the airframe and nonrotatable. It is to be understood,however, that the segment 22 can be fixed, to the air frame with thesegment-21 being rotatable to nest within segment 22 or close theopening 40. A motor 30 is rigidly mounted to the airframe and drives apinion 32 via a transmission 31. The pinion meshes with gear teeth 23formed about the interior surface of the outer segment 22. Serving toreduce friction between the cylindrical segments during movement is abearing 24.

In the closed position of the nozzle 20, as illustrated in FIG. 3, thecross section thereof is approximately round, and the two cylindricalsegments 21 and 22 are provided with suitable interlocking means attheir overlapping longitudinal edges.

During vertical flight, the inner cylindrical segment 22 is rotatedabout its longitudinal axis 13 so as to place the elongated opening ofthe sections 21 and 22 in registering alignment, thus producing anopening 40 through which the primary nozzle 11 tilts for vertical thrustoperation. In this open position, the outer cylindrical segment 22 restsabout the inner cylindrical segment 21, as illustrated in FIG. 4. Thus adownwardly disposed opening is provided for vectoring the primary nozzletherethrough. A feature of the illustrated embodiment is that theaerodynamic conditions of the aircraft remain substantially unchangedregardless of the relative positions of the cylindrical sections 21 and22.

In order to obtain the ejector effect of the secondary nozzle,appropriate fresh air intake ports 25 are defined along the periphery ofthe segments 21 and 22 in the primary nozzle exhaust region, asparticularly illustrated in FIG. 5. The primary nozzle exhaust jetproduces a reactive force which tends to produce a buckling stress uponthe sections 21 and 22. To prevent deformation of the sections, the wallthickness of the critical portions thereof are suitably increased. Whencompared with prior arrangements, the illustrated embodiment results ina considerable saving in space and maintains favorable aerodynamic flowconditions.

Although but one specific embodiment of this invention has been hereinshown and described, it should be understood that certain details of theconstruction shown may be altered without departing from the spirit andscope of this invention.

We claim:

1. An ejector nozzle suitable for use with a jet engine of jetpropelledaircraft, said ejector nozzle comprising a tiltable primary nozzle fordirecting the jet stream from the engine, a secondary nozzle includingnested cylindrical segments axially rotatable with respect to eachother, each of said cylindrical segments defining an elongated axiallyoriented opening, one of said cylindrical segments being fixed to theairframe of said aircraft, and the other of said segments beingrotatable about an axis generally parallel to the longitudinal axis ofthe engine.

2. An ejector nozzle in accordance with claim 1 wherein each of saidcylindrical segments adjacent the exhaust region of the primary nozzledefines fresh air intake ports.

3. An ejector nozzle in accordance with claim 2 wherein the edges ofsaid cylindrical segments defining said elongated openings are providedwith interlocking means.

4. An ejector nozzle in accordance with claim 1 wherein said rotatablecylindrical section rotates through a angle.

5. An ejector nozzle in accordance with claim 1 which further includes amotor drivingly engaged with a pinion gear and a plurality of gear teethformed about the interior surface of said rotatable cylindrical segment,said pinion gear and said gear teeth being in meshing engagement so thatactuation of said motor produces rotational movement of said rotatablecylindrical segment with respect to said fixed cylindrical segment.

